Arylimide-epoxy resin composites

ABSTRACT

Arylimides prepared from oligomer diamines and polyamines and maleic anhydride have been blended with epoxy resins to provide compositions which can be cured to thermoset composites.

I United States Patent [191 260/78 UA, 326.3, 326.5 FM, 326.26, 836,- 837 Kwiatkowski Nov. 18, 1975 ARYLIMIDE-EPOXY RESIN COMPOSITES [75] Inventor: George T. Kwiatkowski, Green [56] l I References Cited Brook, NJ. 2 v UNITED STATES PATENTS [731 Assignees Union Carbide Corporation, New 3,730,948 5/1973 Akiyama et a] 260/47 York, N.Y. Primary ExaminerMelv1n Goldsteln Flledi J 1974 Assistant Examiner-T. Pertilla [2]] Appl NO; 433,114 Attorney, Agent, or FirmB F. Crowe I [57] ABSTRACT [52] US. Cl. 260/837 R; 117/124 E; 161/185; A v f d 260/47 EN; 260/49, 260/59, 260/78 ryhmides prepared rom o igomer lammes an 260/326 260/326 5 260/836 polyamines and malelc anhydrlde have been blended [51] Int Cl 2 C08G 45/12 with epoxy resins to provide compositions which can 58 Field of Search 260/47 EN, 2 N, 59, 49, cured thermos 10 Claims, No Drawings wherein each of R, R", R', and R" is a monovalent ARYLIMIDE-EPOXY RESIN COMPOSITES BACKGROUND OF THE INVENTION This invention pertains to thermosetting resins and 5 more particularly to arylimide/epoxy-resin composites.

Thermosetting resins have been used successfully as molding powders, or laminating and bonding and in coating operations. Representative examples of thermosetting resins include furane resins, phenolformaldehyde resins, melamine-formaldehyde resins, urea-formaldehyde resins, polyester-styrene resins and epoxy resins. These vary in their physcial and chemical properties which determine their various end uses.

It is an object of this invention to provide a resin system suitable for curing to tough thermally stable thermoset composites having high glass transition temperatures (Tg) and high modulus plateaus above the Tg, a combination of properties not readily provided by prior art thermosetting resins.

SUMMARY OF THE INVENTION (x)q 2 A resin composition which can be cured to a thermo- C set composite has been found meeting the object of this invention which comprises: i 2 CH A. about 5 to about 95% by weight of an arylimide Li. 0 having the formula: Z NR C\ n -n-o- -c r D-(Y) II R c (x) CH3 II P O r It wherein D is at least one radical, selected from the DMTHYLACETAMIDE group consisting of:

and IMIDIZATION v Q I! q 0 m-c ca 7 mm -o- ---so r ll fl 12H (10,, cg wherein Y is a radical having the formula: coofi q v O 9 C an C a C C s \N v 1/ Q u (in ill C rm CH R H 5 c)c a a radical selected from the group consisting of H, lower alkyl having 1 to 8 carbon atoms or chlorine,

r is an integer having values of l to 3;

sis an integer having values ofO to 3 with the proviso that when s is O, Y is H or X;

n is an integer having values of l to 5;

k is an integer having values of 0 to 100;

X is halogen selected from the group consisting of F, C1, or Br, and each of q and p are integers having values of 0 to 4, and i B. about to about 5% by weight of an epoxy resin having an average of more than one epoxy group,

CHCH.

per molecule. 7

The preparation of the arylimide components may be best illustrated by the condensation of a diamine with maleic anhydride as shown below:

A more economical process for preparing arylimides involves synthesizing the arylamines in a solvent which allows direct in situ conversion to the corresponding maleimide. O n

ln this case, the sequence of reactions is as follows: 15

1. formation of the sodium salt of p-aminophenol using sodium hydroxide in N-methylpyrrolodinone and in the presence of the chlorinated polyaromatic and an azeotropic solvent; I

2. azeotropic distillation of the water formed fol- 20 lowed by distillation of the azeotropic solvent;

3. completion of the condensation reaction at about l40l 70C.; 4. addition of an equivalent amount of maleic anhydride to the reaction mixture at room temperature; 5. dehydrative imidization of the intermediate N- arylmaleamic acid by addition of acetic anhydride' containing 10% soium acetate; 6. recovery of the product by coagulation from water.

Preferred species represented by the generic aryli- 30 mide formula shown above include the following:

1. Oligomer polysulfone bis(maleimides) having the formula:

2. Oligomer polyphenylene ether maleimides having the idealized formula:

.- 3. Polyphenylene ether maleimides having the idealized formula:

4. Arylether maleimides having the formulai 2 i R l: wflli 5. Oligomer arylether bisphenol A maleimide having the formula:

wherein s is an integer having values of 0 to 3, X is a halogen and preferably chlorine, n is an integer having values of l to 5,

1 is an integer having Values O to 4 and is p P by condensation with maleic anhydride followed by cyy 4, I clization't'o'maleimide as described above for chlorob and k are rational numbers having values of 0 to phenyl amines. Depending on the nature of the amine 100, a used one can obtain a series of maleimmides containing m is an integer having values of 1 m4 and v is a rafrom f? to four imide functlons molecule Those tiona] number having values of 1 to about containing two to four imide functions per molecule are thermosetting resins. While maleimides containing only one imide function are not thermose-tting alone they are when used in combination with the polyfunc- Especially preferred species of the oligomer polysulfone bis(maleimides) depicted in formula (1) above are those having molecular welghts of about 1000 tional maleimides or other thermosetting systems.

1500 and 2500' I Other useful halogenated benzenes which can be Preferred Species of the oligomer p yp y used in this invention include any of the bromo or ether maleimides of formula (2) above are those where fluom derivatives f benzene, diphenyl, terphenyl, m is 3. Those maleimides represented by formula (2) raphenyl, n the like can be readily P p y first Preparing Polyamines 1 In a similar manner the oligomer polyphenylene y condensation of the sodium Salt of Paminophenol ether bis(maleimides) shown by formula (3) above can with a halogenated, preferably chlorinated, polyphenyl be obtained by condensing Sodium p aminophenolate in a highly polar solvent such as dimethylsulfoxide or with polyhalogenated diphgnyl ethem The resultant dimethylfmmamide or N'methylpyrrolidinone 2O amines are then converted to the maleimides. Particulowed by recovery of the Product by coagulation from larly preferred because of its commercial availability is water. The chlorinated polyphenyls thus obtained are a dgcabromodiphenyl ethen multi-component mixture. For example, condensation of three moles of sodium p-aminophenolate with a 60% by weight chlorinated terphenyl (commercially available under the trademark Aroclor 5460 from Monsanto Chemical Co.) afforded a product with a titrated As another variation the oligomer polysulfone bis(- maleimides) shown in formula (1) can be prepared with increased functionality over that of the normally difunctional amines disclosed therein by first preparing polyfunctional amines by condensing sodium aminfi equivalent Weight of paraaminophenolate, the disodium salt of bisphenol Three products were identified by mass spectrome- A,(2,2-bis(p-hydroxyphenyl)propane). dichlorodi- 0 Cl C II 0.9 mol ct-Qs-Qcl 0.1 ml 01- -c1 0 t 01 and C, H Cl (OC I-l NI-l The first two of these prod- 9 3 1.05 mol Na0--Nl-l 0.5 mol rim-@g-Q-om ucts were triamines and the second a diamine. Other polychlorinated benzene reactants which can be used in this invention include hexachlorobenzene, 42% chlorinated biphenyl, (Aroclor 1242 trademark of Mon- 45 santo Chemical Co.) 54% chlorinated biphenyl (Aroclor 1254 trademark of Monsanto Chemical Co.) and 55 the like. In the practice of this invention the condensa- In this particular instance the titrated amine equivation of sodium p-aminophenolate with halogenated hy-, lent weight was 429.

drocarbon can be controlled to afford amines contain- Arylether maleimides represented by formula (4) ing from one amine group to four amine groups. Any of can be prepared as indicated by the following sequence these amines ccan then be converted to maleamic acids of reactions:

maleic Z o 0 R2 anhydride dimethyl m acetamide (in 0 n O in 2 gcetic cu m O--@NH on L \CO H ER Sodium 2 Acetate (x) uo c 0 q Q n u C Cll-l cu 0 0 n l CH m 2 g x o 0 wherein m is a integer having values of l to 4. able composition of this invention is not narrowly criti- Oligomer arylether bisphenol A maleimides reprecal. Any of the epoxy resins commercially available sented by formula (5) can be prepared by 30 which by definition and convention contain more than maleic anhydride 2 dimeth 1 q V acetam de H II CH C

3 CH m M CH II n 1/! cu 3 co H q )1 v uo c acetic anhzdride sodium acetate C 0 II H CH 'Q H H c/ CH H CH The above-described maleimides can be used as B- one vicinal epoxide grouping or oxirane ring, i.e.,

stageable resins for the preparation of glass cloth pre- 65 pregs and adhesives which can be thermally converted to the thermoset state.

The choice of the epoxy resin component in the curcan be used.

Exemplary epoxy resins include the glycidyl ethers of polynuclear polyhydroxy phenols such as bisphenol A, i.e., 2,2-bis (4-hydroxyphenyl)propane, bisphenol F, i.e., bis(4-hydroxyphenyl) methane, trihydroxyl diphenyl dimethylmethane, 4,4-dihydroxylbiphenyl, 1,1- bis(4-hydroxyphenyl)ethane, l ,2-bis(4-hydroxyphenyl) ethane, tetra-(p-hydroxyphenyl)ethane, l,l-bis- (4-hydroxy-2-chlorophenyl)ethane, 1,l-bis-( 3-methyl- 4-hydroxyphenyl) ethane, 1,3-bis (3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-phenyl-4-hydroxyphenyl) propane, 2,2-bis-(3-isopropyl-4-hydroxyphenyl)propane, 2,2-bis-(2-isopropyl-4-hydroxyphenyl)propane, 2,2-bis-(4-hydroxynapththyl) propane, 2,2-bis-(4- hydroxyphenyl) pentane, 3,3-bis-(4-hydroxyphenyl)- pentane, 2,2-bis-(4-hydroxyphenyl)heptane, bis-(51- hydroxyphenyl) phenylmethane, bis-(4-hydroxyphenyl) cyclohexylmethane, l,2-bis-(4-hydroxyphenyl)- l,2-bis-(phenyl)propane, 2,2-bis-(4-hydroxyphenyl)- l phenyl-propane and the like; di(hydroxyphenyl)sulfones such as bis-(4-hydroxyphenyl)-sulfone, 2,4 '-dihydroxydiphenyl sulfone, 5'-chloro-2,4-dihydroxydiphenyl sulfone, 5-chloro-4,4-dihydroxydiphenyl sulfone, and the like; di(hydroxyphenyl) ethers such as bis-(4- hydroxyphenyl)-ether, the 4,3-,4,2-,2,2-, 2,3-dihydroxydiphenyl ethers, 4,4-dihydroxy-2,6-dimethyldiphenyl ether, bis-(4-hydroxy-3-isobutylphenyl)- ether, bis-(4-hydroxy-3-isopropylphenyl)-ether, bis-(4- hydroxy-S-chlorophenyl)-ether, bis-(4-hydroxy-3- fluorophenyl)-ether, bis-(4-hydroxy-3-bromophenyl)- ether, bis-(4-hydroxynaphthyl)-ether, bis (4-hydroxy- 3-chloronaphthyl)-ether, 4,4-dihydroxy-2,6-dimethoxydiphenyl ether, 4,4-dihydroxy-2,5-diethoxydiphenyl ether, and the like; the diglycidyl ethers of mononuclear phenols such as:

hydroquinone pyrocatechol resorcinol saligenin phloroglucinol p-aminophenol, and the like;

epoxidized cycloaliphatic olefins such as:

3,4-epoxycyclohexylmethyl-3,4-epoxy-cyclohexane carboxylate bis(3,4-epoxy-6-methylcyclohexylmethyl adipate o 0 N H c11 awe-C -O-CH2 CH H 0 bis (2,3-epoxycyclopentyl)ether and the like, and

Epoxylated novolac resins such as those described in Epoxy Resins by H. Lee and K. Neville, pages 18-20, McGraw-l-lill Book Co., Inc. (1957) as having the gen- 5 eral structure:

this invention do not require a curing or hardening agent to effect their conversion to a tough thermoset composite. Curing by heating is sufficient to achieve this state with temperatures in the range of about 220 20 to about 280C. being preferred although temperatures in the range of about 150C. to about 350C. can be used.

Although a curing or hardening agent is not required one can be used if desired as for example an amine, an anhydride, or a phenol.

Representative amines include aliphatic amines, such as, diethylene triamine, triethylene tetraamine, dimethylamino propylamine, and the like; aromatic amines, such as metaphenylene diamine, 4,4-methylene dianiline, diamino diphenyl sulfone; aralkyl amines such as, benzyldimethylamine, 2-methylbenzyl dimethylamine, dimethylamino methyl phenol, and the like.

Exemplary anhydride curing agents are tetrahydrophthalic anhydride, phthalic anhydride, pyromellitic dianhydride, maleic anhydride, dichloromaleic anhydride, dodecenyl succinic anhydride, chlorendic anhydride, and the like.

Examples of phenolic curing agents include bisphenol A or 2,2-bis(p-hydroxyphenyl)propane, trisphenol as well as phenol aldehyde condensation resins containing phenolic residues such as the novolaks.

The fabricating annd mechanical properties of the composites produced by this invention are superior to those of either the arylimide component or the epoxy component when cured alone. This is demonstrated by such properties as:

1. Glass transition temperatures 200C,

2. Modulus plateaus above the Tg of 10 dynes/cm 3. Low pressure fabrication requirements, and short post cure requirements,

4. Outstanding thermal and oxidative stability at 260C. and above, and

5. Good hydrolytic stability.

Although about 5 to about 95% by weight of arylimide can be used in the thermosetting compositions of this invention, it is preferred to use about to about by weight.

The arylimides and epoxy resins can be blended together using conventional mixing equipment such as a Banbury mixer, two roll mill and the like.

These thermosetting resin compositions can be used for the fabrication of molded articles, laminates and graphite composites as well as adhesives and friction or abrasive binders.

The invention is further described in the examples which follow. All parts and percentages are by weight unless otherwise specified.

EXAMPLE 1 the determination of secondary glass transitions. The

determlnatlon of G, the real part ofthe complex shear Preparation of Arylimide from Moles of modulus, has significance in that G versus temperature P'Aminophenol and moles of Aroclor 5460 resembles an E-T curve which is commonly used for polymer characterization. G", the imaginary part of the complex shear modulus, represents the viscous component of the shear modulus. Therefore peaks for G" versus temperature also correspond to transitions. A detailed explanation for determining the Tg, shear A 36 gallon reactor equipped with a stirrer, thermocouple, nitrogen inlet, condenser and water-xylene separator was charged withf p-Aminophenol 15.14 lbs.

Aroclor 5460 (60% chlorinated modulus, and shear modulus plateau can be found in X one lerphenyl) :5 Mechanical Properties of Polymers by L. E. Nielson, NyMethylpyrondinone Reinhold, New York (1962). High values for the tensile modulus plateau above the Tg, indicate high-crosslinked density of specimens so tested. Tensile modulus The reactor was Sparged wnh nitrogen and heated to was calculated from shear modulus measurements.

reflux. At reflux, 11.05 lbs. of NaOH solution (49.7%) was added slowly over 1 hour.

After completion of the sodium hydroxide addition, EXAMPLE 2 the system was dehydrated. Xylene was then distilled Exmple l was repeated using a blended mixture go off until a pot temperature of 165C was attained. The grams of the arylimide prepared in Example ](A) and mlxture was then stirred for 0.5 hour at 165 C. and 10 grams of epoxylated novolak describadil1 Example cooled to room p 1(B). The resulting blend was B-staged for 4 minutes at At room temperature, Of maleic anhydride and molded under pressure at 265C for 5 minwere added over an pp x y 10 minute period to utes. The resulting plaque was post-cured at 265C. for minimize any exotherm. The reactor contents were 1 ho d ed for testing. then stirred 1 hour at room temperature and 14.17 lbs. T i dulum da a indicated a Tg at 232C., a 0f acetic anhydride and 2.71 lbs. of sodium acetate tensile modulus plateau of 48,000 psi and a hear modwere added. After stirring at room temperature for 2 l l t of l,1 10 (lyrics/c111 hours, the material was discharged from the reactor.

The product was recovered by coagulation in five times its volume of water. The precipitated material EXAMPLE 3 was collected by filtration and the filter cake re-slurred Example I was repeated with the exception that 30 in water and refiltered. The product was then dried to grams of BAKEUTE liquid p y resin ERL'2772 a constant i h at 65C. under vacuum (trademark for a diglycidyl ether of bisphenol A having The material exhibited a melting point of 97-l 13C. a iscosity at 25C. of 7.00 c n ip es, an ap- Torsion pendulum data obtained on a cured sample in- Parent p fi g y 0f and an dicated a Tg at 255C. and amodulus plateau about the p xy q i alent (grams/gram mol f Xira xyg Tg of 4.2 X 10 dynes/cm of 175-185) was used in place of the epoxylated novo' lak. The resulting blend was B-staged for 4 minutes at Blendmg of Aryhmd's Epoxylated Novolak 40 265C. and molded under pressure at 265C. for 5 min- A mixture of grams of the arylimide prepared in utes. The resulting plaque was post-cured at 265C. for

(A) and 30 grams of an epoxylated novolak having an I hOUl and used for testing. Torsion pendulum data inepoxy equivalent of 180-220g,/g ol oxirane oxygen dicated a Tg at C. and a tensile modulus plateau at and believed to have the idealized formula: 1.0 X 10 dyneslcm (|)C1-1 -Cl-l cs ocu -cu c11 O-CH -CH cs 0 CH @D/ cs9 t (where t has an average value of 6) EXAMPLE 4 was melt blended on a two roll mill at C. The blend 55 Example 1 was repeated with the exception that the was B'Staged at 265C 5 2 mmutes and finally epoxylated novolak was replaced by 30 grams of a tetcompwsslo'l molded at 265 for 3 g The raglycidyl ether of tetra (p-hydroxyphenyl ethane hav- 4X4X0.040 lnch plaque was postcured at 265 C. for 60 ing an epoxy equivalent of 190440 grams/gram mole minutes and used for the measurement of mechanical 60 of oxirane oxygen After melt blending at 250C for 7 propelities of the thermoset composite obtained minutes to attain a B-staged uniform blend, the mixture Torsion pendulum of the thermoset composlte was compression molded at 265C. for l hour. The torlndlcated a glass transition temperature, Tg. of C. Sion pendulum data indicated a T8 of 215C for the a tznslle g l f l l i lgi g l 2 composite with a room temperature shear modulus of l m0 2% 8 5 1032! a 5 car 65 1.35 X 10 and a shear modulus above the Tg of 6.0 X

mo u us a ove e o ynes cm I08 A torsion pendulum apparatus was used for these composite characterization measurements. The most EXAMPLE 5 important aspect of the torsion pendulum data involves A laminate was P p y Preparing a Solution of 30 parts ofa triglycidyl ether of p-aminophenol having r is an integer having values of l to 3, an epoxy equivalent of 105-115 grams/gram mole of s is an integer having values of to 3, with the prooxirane oxygen and a viscosity at 25C. of 1500-5000 viso that when s is O, Y is H or X centipoises (BAKELITE ERL-OSOO) and 70 parts of n is an integerhaving values of l to 5, the arylimide prepared in Example 1 in I30 parts of k is an integer having valuesof 0 to 100, methylethyl ketone. Glass cloth treated with 3-amino- X is a halogen selected from the group consisting of propyl trimethoxysilane was impregnated by dipping 1 F, Cl, or Br and, into the methylethyl ketone-resin solution and then each of q and p are integers having values of 0 to 4, drying the cloth in an air circulating oven at 60-80C. "O and The resulting glass cloth prepregs were consolidated at 8. about 95 to about 5% by weight of an epoxy resin 200C. under a pressure of 100 psi to afford tough nine having an average of more than one epoxy group, 7 ply laminates which could not be delaminated. These p laminates can be used in electrical and structural applications. 0

Although the invention has been described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred P f has been made only by way of example and that 2. Composition claimed 1n claim I wherein D 15 v numerous changes may be resorted to without departing from the spirit and scope of the invention.

What is claimed is: O l. Thermosetting resin composition consisting essentially of n A. About 5 to about 95% byweight of an arylimide having the formula: I

o )s CH3 wherein D is at least one rdical selected from the 3. Composition claimed in claim 2 wherein n is 3 and group consisting of: X is Cl.

4. Composition claimed in claim 1 wherein D is SO and o 2 X 0Q 4o p 5. Composition claimed in claim 1 wherein s and r q q are each 1.

wherem Y Is a radical havmg the formula: 6. Composition claimed in claim 1 wherein R, R",

2 R'0OR" are each H.

m 7. Composition claimed in claim 1 wherein the epoxy C R resin is a diglycidyl ether of 2,2-bis (p-hydroxyphenyl)- o v N n propane C 8. Composition claimed in claim 1 wherein the epoxy C R"" resin is an epoxylated novolak. II o 9. Composition claimed in claim 1 wherein the epoxy resin is a tetraglycidyl ether of tetra (p-hydroxywhe phenyl )ethane.

each of r, R", R' and R"" is a monovalent radil d f h group consisting of H 10. Composition claimed in claim 1 wherein the lower alkyl having 1 to 8 carbon atoms or chlop y {65in is a triglycidyl ether of p' p 13233 UNITED STATES PATENT OFFICE CERTIFICATE OF CQRRECTION Patent No. 3, 920, 768 Dated Nov. 18, 1975 Invento George T. Kwiatkowski It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4 in the first formula the hydrogen atom on the N within the right hand bracket should be removed Claim 1, column 14, the formula at line 15 should read:

[SEAL] Arrest:

I RUTliC. MAISON I Q C. MARSHALL DANN A! "81mg /7 0 (ommimrmer oj'Parents and Trademarks Thirteenth Day of Iuly 1976 

1. THERMOSETRING RESIN COMPOSITION CONSISTING ESSENTIALLY OF A. ABOUT 5 TO ABOUT 95% BY WEIGHT OF AN ARYLIMIDE HAVING THE FORMULA:
 2. Composition claimed in claim 1 wherein D is
 3. Composition claimed in claim 2 wherein n is 3 and X is Cl.
 4. Composition claimed in claim 1 wherein D is
 5. Composition claimed in claim 1 wherein s and r are each
 1. 6. Composition claimed in claim 1 wherein R'', R'''', R''0''''OR'''''''' are each H.
 7. Composition claimed in claim 1 wherein the epoxy resin is a diglycidyl ether of 2,2-bis (p-hydroxyphenyl)propane
 8. Composition claimed in claim 1 wherein the epoxy resin is an epoxylated novolak.
 9. Composition claimed in claim 1 wherein the epoxy resin is a tetraglycidyl ether of tetra (p-hydroxyphenyl)ethane.
 10. Composition claiMed in claim 1 wherein the epoxy resin is a triglycidyl ether of p-aminophenol. 